Rectifier discharge tube and method of sealing the anode leadin



D. G. S. RUHWANDL RECTIFIER DISCHARGE TUBE AND METHOD OF SEALING THE ANODE LEADIN Filed Feb. 14, 1947 Feb. s, 1949.

IN VENTOR D.G.S. RUHWANDL Patented Feb. 8, 1949 RECTIFIER DISCHARGE TUBE AND METHOD OF SEALING THE ANODE LEADIN Dominicus Gerardus Serge Ruhwandl, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford,

Conn, as trustee Application February 14, 1947 Serial No. 728,565 In Belgium December 15, 1944 Section 1, Public Law .690, August 8, 1946 Patent expires December 15, 1964 3 Claims.

To avoid that in a discharge tube the discharge settles on a metal leading-in member or an electrode terminal, the attempts have always been directed to separating all metal parts of the leadthrough arrangement from the discharge space. To such end these parts have often been covered with insulating materials. Thus, for instance, electrode terminals have usually been surrounded by tubes of ceramic material, the lead-in members e. g. metal lead-in bushings often being furnished with an internal glass coating. However, the methods hitherto used suffer from drawbacks. It has been found, for instance, that upon sealing lead-in bushings the glass covering melts and flows due to the high temperature, so that it is difiicult to obtain a uniform glass coating. Other constructions, in which this drawback is avoided, require much and consequently expensive handiwork.

I have now devised a new construction, in which in a discharge tube all metal parts of the leadthrough arrangement are completely separated from the discharge space, without trouble being experienced from the aforesaid drawbacks. To this end, according to the invention, the wall of the tube, the lead-in member for an electrode and the coating of the electrode terminal are mechanically interconnected by scaling to a glass moulding having at least three sealing edges. This glass moulding preferably has a cylindrical or conical portion, the outer wall of which is possessed of a flange. In this way the discharge space is entirely separated from the lead-in member and the electrode terminal and more particularly by the glass moulding and the envelope of the terminal, which parts are sealed together, so that even no cleft is left for the passage of the discharge.

In order that the invention may be clearly understood and readily carried into eifect it will now be described more fully with reference to the accompanying drawing which represents, by way of example,one form of construction of the discharge tube according thereto.

The bulb l contains a cathode, and an anode. The cathode is provided in the cathode screen 2 and is not represented. Ihe anode 3 is carried by the anode terminal 4 which is surrounded by an insulating tube 5, for instance of steatite. To this tube is secured, by means of a clip 1, the anode screen 6 which preferably consists of metal. The anode terminal 4 is introduced into the discharge tube through the intermediary of a metal bushing 8, for instance of chrome iron. The wall.

1 of the discharge tube, the bushing 8 and the steatite tube 5 are interconnected by scaling to the glass moulding Qhaving three sealing edges. By making use of such a glass moulding the manufacture of the discharge tube is greatly simplified,

whilst obtaining an ideal separation of the supply members from the discharge space.

What I claim is:

1. A discharge tube having a cathode and an anode in a glass envelope, with a lead-in connection to the anode consisting of a metallic conduc tor having its inner end secured to the anode body, a refractory tube encircling and spaced from the conductor with one end of the refractory tube tightly secured to the anode body to seal-0E the conductor at that region, a cylindrical glass moulding piece having a body section encircling the lead-in conductor in'spaced relation thereto, with the inner end of the moulding piece 1 sealed to the outer end of the refractory tube and the outer end of the moulding piece sealed to a metal element on the body of the lead-in conductor, and a glass seal connection between the outer side wall of the moulding piece and the envelope.

2. A discharge tube as in claim 1, in which the moulding piece consists of a cylindrical body section with a flange on the outer wall and of a dimension corresponding to the outer diameter of the anode, whereby the anode member during manufacturing assembly may be inserted through an opening in the envelope and the flange then REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,953,033 Widmer Mar. 27, 1934 2,117,794 Duinker et a1. May 17, 1935 2,320,685

Bertele June 1, 1943 

